112 lines
3.5 KiB
Markdown
112 lines
3.5 KiB
Markdown
# Basics for hacking on Clippy
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This document explains the basics for hacking on Clippy. Besides others, this
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includes how to set-up the development environment, how to build and how to test
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Clippy. For a more in depth description on the codebase take a look at [Adding
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Lints] or [Common Tools].
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[Adding Lints]: https://github.com/rust-lang/rust-clippy/blob/master/doc/adding_lints.md
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[Common Tools]: https://github.com/rust-lang/rust-clippy/blob/master/doc/common_tools_writing_lints.md
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- [Basics for hacking on Clippy](#basics-for-hacking-on-clippy)
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- [Get the code](#get-the-code)
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- [Setup](#setup)
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- [Building and Testing](#building-and-testing)
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- [`cargo dev`](#cargo-dev)
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## Get the Code
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First, make sure you have checked out the latest version of Clippy. If this is
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your first time working on Clippy, create a fork of the repository and clone it
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afterwards with the following command:
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```bash
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git clone git@github.com:<your-username>/rust-clippy
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```
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If you've already cloned Clippy in the past, update it to the latest version:
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```bash
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# upstream has to be the remote of the rust-lang/rust-clippy repo
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git fetch upstream
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# make sure that you are on the master branch
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git checkout master
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# rebase your master branch on the upstream master
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git rebase upstream/master
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# push to the master branch of your fork
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git push
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```
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## Setup
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Next we need to setup the toolchain to compile Clippy. Since Clippy heavily
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relies on compiler internals it is build with the latest rustc master. To get
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this toolchain, you can just use the `setup-toolchain.sh` script or use
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`rustup-toolchain-install-master`:
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```bash
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sh setup-toolchain.sh
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# OR
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cargo install rustup-toolchain-install-master
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# For better IDE integration also add `-c rustfmt -c rust-src` (optional)
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rustup-toolchain-install-master -f -n master -c rustc-dev -c llvm-tools
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rustup override set master
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```
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_Note:_ Sometimes you may get compiler errors when building Clippy, even if you
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didn't change anything. Normally those will be fixed by a maintainer in a few hours.
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## Building and Testing
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Once the `master` toolchain is installed, you can build and test Clippy like
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every other Rust project:
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```bash
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cargo build # builds Clippy
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cargo test # tests Clippy
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```
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Since Clippy's test suite is pretty big, there are some commands that only run a
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subset of Clippy's tests:
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```bash
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# only run UI tests
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cargo uitest
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# only run UI tests starting with `test_`
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TESTNAME="test_" cargo uitest
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# only run dogfood tests
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cargo test --test dogfood
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```
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If the output of a [UI test] differs from the expected output, you can update the
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reference file with:
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```bash
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sh tests/ui/update-all-references.sh
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```
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For example, this is necessary, if you fix a typo in an error message of a lint
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or if you modify a test file to add a test case.
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_Note:_ This command may update more files than you intended. In that case only
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commit the files you wanted to update.
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[UI test]: https://rustc-dev-guide.rust-lang.org/tests/adding.html#guide-to-the-ui-tests
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## `cargo dev`
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Clippy has some dev tools to make working on Clippy more convenient. These tools
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can be accessed through the `cargo dev` command. Available tools are listed
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below. To get more information about these commands, just call them with
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`--help`.
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```bash
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# formats the whole Clippy codebase and all tests
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cargo dev fmt
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# register or update lint names/groups/...
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cargo dev update_lints
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# create a new lint and register it
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cargo dev new_lint
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# (experimental) Setup Clippy to work with rust-analyzer
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cargo dev ra-setup
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```
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